<!DOCTYPE html>
<html lang="en">
<head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .test1,.test2{
            width: 200px;
            height: 200px;
            border: 10px solid red;
            background-color: #64ff75;
            box-sizing: content-box;
        }
        .test2{
            box-sizing: border-box;
        }
    </style>
</head>
<body>
    <div class="test1"></div>
    <br>
    <br>
    <div class="test2"></div>
</body>
</html>